Heat-transforming apparatus



y 1930- R. w. DAVENPORT 1,758,074

HEAT TRANSFORMING APPARATUS Filed March 10, 1927 INVENTOR. Ransom 14 0avenp 0 7 A TTORNE Y.

Patented May 13,1930

PATENT oFFIcEi RANSOM W. DAVENPORT, OF PETROIT. MICHIGAN, ASSIGNOR TOCHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y.,' A CORPORATION 01?NEW JERSEY HEAT-TRANSFORMING APPARATUS Application filed March 10, 1927.Serial No. 174,267.

This invention relates to processes and aparatus for transforming heatand particuarly to refrigerating systems. More particularly it concernsclosed cycle refrigerating systems using Working substances of the classwhich comprises a solution of a lubricant in a volatile liquid.Lubricating refrigerants of the described type are disclosed in mycopending application, Serial No. 60,311, filed October 3rd, 1925.Processes and apparatus providing for the circulation of such alubricating refrigerant through a closed circuitin whichthe volatilecomponent is used for producing refrigeration and the less volatilecomponent for lubrication, are disclosed in my copending applicationSerial No. 88,164, filed Feb. 15, 1926 of which the present invention isin the nature of an improvement. My last named application relates tothe step which involves maintaining a body of lubricant solution underthe temperature and pressure of discharge from a refrigeratingcompressor to give the vapor of the volatile component time to distilloff, thus concentrating the lubricant which is then returned hot to thelubricating system of the compressor.

One object of the present invention is to provide improved ways andmeans for using lubricating refrigerants of the described type. Anotherobject is to control the viscosity of the lubricating ingredient whichis fed back to the lubricating system. Other objects will be apparentfrom the detailed description which follows:

In the present invention, previously disclosed processes and apparatusare improved by the addition of ways and means for performing anadditional step with a view to securing better lubrication of the movingparts and'more perfect sealing of thespaoes which must hold compression.It has been discovered that lubricant after having come to equilibriumwith the volatile vapor at the temperature and pressure of discharge maythen be cooled, thereby increasing its viscosity and improving itssealing and lubricating properties. The cooling step, however, must beperformed out of direct surface contact with the hot vapor of thevolatile component had to the accompanying drawing which showsdiagrammatically a closed cycle refrigerating system with the compressorand associated parts in vertical section.

The essential elements of the refrigerating system disclosed are thepump or compressor, 1., the condenser 2, and the evaporator 3. Asuitable feeding device or so called expansion valve 4 controls thefeeding of the working substance from condenser 2 to evaporator 3. Sincethese essential elements of the system may be of any suitable or desiredtype, the condenser 2 and evaporator 8 are indicated diagrammaticallyand a conventional form of pump or compressor is illustrated in section.A suitable lubricatin g system is provided for the pump such as a bodyof lubricant 5 in the crank case arranged to reach the moving parts ofthe pump by the s lash from the crank shaft and connecting ro s.

In the form of system shown, pump 1 is arranged to withdraw fromevaporator 3 through communicating conduit 6, the vapor of therefrigerant and discharge the same into condenser 2 whence thecondensate is fed back to evaporator 3 through feeding device 4. As inmy copending application Serial No. 88,164, the system provides for theseparation of the refrigerant into its volatile and non-volatilecomponents upon the high pressure side of the system at the hightemperature of compression and" by fractional distillation. To this enda still 7 is provided between condenser 2 and compressor 1 and intowhich the compressor discharges through conduit 8. Still 7 is maintainedat the desired high temperature to effect fractional distillation of thecompressed vapor in any suitable manner as by covering the still withheat insulating material or by the application of heat thereto, ifnecessary. The fluids discharged by pump 1 are retained in still 7 asufficient period to enable the components' of the working substance toseparate. The distillate or lubricant gathers in the lower part of still7 .below the inlet opening and is drawn off by a pipe 9 which returnsthe lubricant to the lubricating system of the compressor, while thevapor of the volatile component of the working substance passes fromstill 7 by a conduit 10 to condenser 2 and thence back to evaporator 3.

The system as heretofore described does not differ substantially fromthe disclosure of my aforesaid copending application Serial No. 88,164.The present invention has to do particularly with the treatment of thelubricant after it enters conduit 9 and before it passes into the crankcase of compressor 1.

' As shown, pipe 9 is of relatively small bore and of considerablelength and extends to a point beneath the crank case of the compressorwhere it expands into an enlarged cooling coil 9 which extends upwardlyand connects with the crank case above'the oil level therein.Connections 9, 9 accordingly form a trap so that the unbalanced pressuredue to the crank case tending to run under reduced pressure may becounter-poised by the column of oil in the coil. Any suitable or desiredmeans may be provided for removing heat from the lubricant trapped incoil 9*. The most effective means for this purpose utilizes a cool orcold liquid such as water and by preference coil 9 is arranged to beimmersed in such a liquid. To this end a casing 11 encloses the coil andis arranged to be continuously or intermittently supplied with waterthrough pipe 12 which may connect with the water supply for the coolingof cendenser 2 in the event that water is used for that purpose. Thecooling water which enters the top of casing 11 passes off into a wastepipe 13. With this arrangement the cooling of the hot oil which isseparated out in still 7 is effected practically out of direct surfacecontact with the hot vapor retained in adiabatic still 7, since theconnecting pipe 9 is restricted to a very small area for this verypurpose. In consequence the hot oil which passes countercurrent to thecooling water through coil 9 passes into the crank case of compressor 1in a cool'condit-ion and of much higher viscosity than when it leavesthe compressor. By thus maintaining cool oilin the crank case theoperating characteristics of the pump are improved and larger clearancesare permissible without impairing the operation of the same.

In full detail the operating process of the apparatus herein disclosedcomprise the following steps:

1st :-Compressing the vapor of the refrigerant and raising itstemperature and pressure in the compressor;

2nd :-Mixing the vapor with lubricantwhich works into the compressionspace;

3rd z- -Discharging the hot mixture into a vessel or still andadiabatically effecting equilibrium between the vapor phases and theliquid phases of the mixture by allowing the same to remain for a timewith the said phases in contact; 0

4th:-Removing some of the liquid phase and cooling it out of contactwith the hot vapor phase;

5th :--Returning the liquid at approxi mately the temperature of thecooling medium or environment into the compressor and there using it forsealing and lubrication;

6th :Conducting some of the vapor from the adiabatic still into acondenser and cooling the same to liquefy the vapor;

7th :Feeding the condensed vapor into the evaporator; and b8th:Evaporating the liquid to produce refrigeration.

While both the process and the apparatus aspects of the invention havebeen herein disclosed in what is now considered to be a preferred form,it is to be understood that the invention is not limited to the specificdetails thereof, but covers all changes, modifications and adaptationswithin the scope of the appended claims.

I claim as my invention:

1. In a closed cycle refrigerating system in which the working substancehas dissolved therein lubricant from the lubricating system, the processof continuously separating out said lubricant at the high temperature ofcompression, extracting heat from the separated lubricant while out ofcontact with the hot vapor phase of the refrigerating system, andreturning the separated and cooled lubricant to the lubricating system.

2. In a heat engine of the compressor-condenser-evaporator typeutilizing a working substance having lubricant in solution, the processof transforming heat which coniprises circulating said working substancethrough said engine in a closed cycle, continuously effecting separationof the lubricant from the working substance at one point substantiallyadiabatically, removing the separated lubricant from the zone ofseparation, and removing heat from the separated lubricant to restoreits viscosity.

3. In a heat engine of the compressor-condenser-evaporator typeutilizing a working substance having lubricant in solution, the processof transforming heat which comprises circulating said substance throughsaid engine in a closed cycle, continuously effecting separation of thelubricant from the worklng substance at one point substantiallyadiabatically by fractional distillation, removing the separatedlubricant from the zone of separation, and removing heat from theseparated lubricant to restore its viscosity.

4. In a closed cycle system of the compressor-condenser-evaporator typeutilizing mutually soluble substances for refrigeration and forlubrication the process of preventing or nullifying the effects ofleakage between the refrigerating system and the lubricating systemwhich comprises the continuous separation of lubricant from therefrigerant substantially adiabatically on the high pressure side of thesystem and gradually returning the separated lubricant in a relativelycool of the volatile ingredient at the temperature of discharge fromsaid compressor under substantially adiabatic conditions, removing aportion of said solution from contact with said vapor, cooling saidportion to approximately the temperature of said condenser, and feedingthe cooled solution back to said compressor while condensing, feedingand evaporating the volatile ingredient to transform heat.

6. In a closed cycle system of the compressor-condenser-evaporator typehaving a lubricating system for the compressor, the thermodynamicprocess which comprises compressing the Vapor of the refrigerant andraising its temperature and pressure in the compressor, mixing the hotcompressed vapor with lubricant which works out of the lubrieatingsystem, retaining the hot discharged mixture at its high temperature toeffect separation of the lubricant by fractional distillation, movingthe separated lubricant out of contact with the hot vapor phase of therefrigerating system, extracting heat from the separated lubricant,returning the cooled lubricant to the lubricating system, condensing thehot refrigerant vapor in the condenser to liquefy the same, feeding theliquid refrigerant to the evaporator and evaporating the same to producerefrigeration, and continuously repeating the above steps,

7 In a heat engine having a compressor, a condenser, an evaporator, andconnections to form a closed cycle system through which the workingsubstance is circulated, a lubricating system for said compressorcontaining lubricant soluble in said working substance, means operatingsubstantially adibatically at the heat of compression forseparating'lubricant from the Working. substance, means for returningthe separated lubricant to the lubricating system, and means forrestoring the viscosity of the separated lubricant while out of contactwith the hot vapor phase of said system.

8. In a heat engine having a compressor, a-

' substance therein and conducting it into said lubricating systems, andmeans for extracting heat from said separated substance while out ofcont-act with the hot vapor phase of said cycle and before it enterssaid lubricating systems. 1

9. In a heat engine having a compressor, a condenser, an evaporator andconnections to form a closed cycle system through which a workingsubstance is circulated, a lubricating system for said compressorcontaining lubricant soluble in said working substance, means forfractionally distilling out from said working substance at the high heatof compression any lubricant which becomes mixed with said workingsubstance and conducting it into said lubricating system, and means forextracting heat from said separated lubricant while outof contact withthe hot vapor phase of said cycle and before it enters said lubricatingsystem.

10. In a heat engine having a compressor, a

condenser, and an evaporator for a working substance comprising asolution of lubricant in a volatile liquid, means for maintainingsolution and vapor discharged from said compressor in contact withoutsubstantial loss of heat while equilibrium is reached, means forremoving a portion of the solution out of contact with the vapor phaseand for cooling said portion, and means for feeding said cooled portioninto said compressor to lubricate and seal the moving parts thereof.

11. A refrigerating system comprising a compressor, a condenser and anevaporator connected together to form a. closed circuit for the workingsubstance, a lubricating system for said compressor containing lubricantsoluble in the working substance, thermally operated means intermediatesaid compressor and said condenser for continuously separating outlubricant from said working substance, means for moving said separatedlubricant out of contact with said thermal means, and means forextracting heat from said separated lubricant and feeding the same tosaid compressor.

12. A heat engine utilizing a working substance containing lubricant insolution comtrap in said connection, and means for cooling the lubricantin said trap. I

13. A heat engine utilizing a working substance containing lubricant insolution comprising a compresser, a condenser and an evaporatorconnected together to form a closed thermodynamic circuit, a still inthe connection between said compressor and said condenser for separatingthe lubricant from the volatile component of the working substance, aconnection for conducting the lubricant from said still to saidcompressor, said connection having means for maintaining a body of thelubricant substantiallyout of contact with the hot vapor in said still,and means for cooling said body of lubricant.

14. A heat engine utilizing a working substance containing lubricantcomprising a compressor, a condenser and an evaporator connectedtogether to form a closed thermodynamic circuit, a still in theconnection between said compressor and said condenser for separating thelubricant from the volatile component of the working substance, aconnection for conducting the lubricant from said still to saidcompressor, said connection providing a trap and having a restrictedportlon exposing only a small surface area of lubricant to the hot vaporin said still, and means directing cooling fluid counter-current to themovement of lubricant in said trap.

15. A heat engine utilizing a working substance containing lubricant'comprising a compressor, a condenser and an evaporator connectedtogether to form a closed thermodynamic circuit, a still in theconnection between said compressor and said condenser for separating thelubricant from the volatile component of the working substance, aconnection for conducting the lubricant from said still to saidcompressor, said connection providing a trap and having a restrictedportion exposing 0111 a small surface area of the lubricant to the liotvapor in said still, and means for immersing said trap portion of saidconnection in cooling liquid.

16. Refrigerating apparatus utilizing a. working substance containinglubricant in solution comprising a compressor, a condenser and anevaporator connected together to form a closed thermodynamic circuit forsaid working substance, a still in the connection between saidcompressor and said condenser arranged to operate substantiallyadiabatically at the heat of compression for separating out thelubricant component of the working substance by fractional distillation,means for feeding the separated lubricant to the crank case of saidcompressor including a conduit of restricted bore and of substantiallength providing a trap, and means for bringing the trapped lubricantinto thermal contact with a cooling fluid to remove heat from and toincrease the viscosity of the lubri cant.

17. Refri crating apparatus utilizing a working su stance containinglubricant in solution comprising a compressor, a condenser and anevaporator connected together to form a closed thermodynamic circuit forsaid working substance, a still in the connection between saidcompressor and said condenser arranged to operate substantiallyadiabatically at the heat of compression for separating out thelubricant component of the working substance by fractional distillation,means. for feeding the separated lubricant to the crank case of saidcompressor including a conduit of restricted bore and of sub stantiallength terminating in a coil forming a trap and means for passingcooling fluid over said coil to cool the separated lubricant and toincrease the viscosity of the same.

18. Refrigerating apparatus utilizing a working substance containinglubricant in solution comprising a compressor, a condenser and anevaporator connected together to form a closed thermodynamic circuit forsaid working substance, a still in the connection between saidcompressor and said condenser arranged to operate substantiallyadiabatically at the heat of compression for separating out thelubricant component of the working substance by fractional distillation,means for feeding the separate lubricant to the crank case of sa1dcompressor including a conduit of restricted bore and of substantiallength merging into an ascending coil of increased size, a casingenclosing said coil, and means for passing water through said casing andover said coil counter-current to the movement of lubricant therein forremoving heat from and for increasing the viscosity of the lubricant.

Signed by me at Detroit, in the county of Wayne and State of Michigan,this 7th day of March, 1927.

RANSOM W. DAVENPORT.

